On Fri, May 2, 2025 at 01:55 PM, Macrohenry wrote:
When I use the Universal Op Amp or Universal Op Amp 1 as a comparator, the output chart changes from V to MV.? ...
Which op-amp did you use?
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LTspice's "opamp" is an unbounded ideal op-amp.? In the absence of feedback, its outputs could become indefinitely large, either positive or negative.? Perhaps they reach only 1 MegV because of the input signal amplitude combined with the finite voltage gain.
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Please read the information that comes up with LTspice's UniversalOpAmp1 when you select it.? It says this:
A linear, single pole op amp with no
internal nodes or output voltage range
limit. ...
It seems it is behaving exactly as expected.? It has nothing to limit its output voltage range, so it reaches a value determined by the input differential voltage and the open-loop voltage gain.
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UniversalOpAmp1 is not a good choice.? I regret that Analog Devices left it there as a choice.? If I remember correctly, UniversalOpAmp2 was the only one that had been listed in the parts selector, and it was a better choice.? The others could be selected as an override, but #2 was the better one to start with.
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For the life of me, I can't get the comparator to work.?
Use a better one!? Such as UniversalOpAmp2.
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When I try the MAX9095 comparator, the display is not in MV, but the comparator output is a straight DC line.
Seems like it is not working.? Maybe you did something wrong.
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Andy
